This invention relates to the field of air cleaners, and particularly to two-stage air cleaners which include a first, centrifugal stage, or precleaning stage, for removing large particles borne in the air, and a second, filtering stage, in which the filtering means include an outer, principal filter enclosing an inner, "safety" filter.
In such cleaners the filters must be removable for servicing, and such removability often results in crevices through which uncleaned air may be drawn without having its burden of particulate matter removed. When this happens, the cleaner is at least partially inoperative, and damage to equipment downstream in the air line may result.